1. Field of the Invention
The present invention is directed to a synchronizer and more specifically to a pair of synchronizer rings carried by a coupling sleeve for frictional engagement with said gears to facilitate positive coupling of said sleeve with said gears.
2. Prior Art
Synchronizers of the type shown in the U.S. Pat. No. 3,078,975 to Eaton are comprised of a pair of axially spaced apart friction rings which are coupled to each other by a plurality of blocker pins which extend through corresponding recesses in a coupling sleeve. A plurality of energizer pins are also coupled between the two rings and extend through a separate set of apertures in the coupling sleeve. The energizer pins are each comprised of a hollow split sleeve having spring means therein for biasing the halves of the sleeve into engagement with the apertures through which they extend. Since the blocker pins and the energizer pins each have a number of parts the total number of parts for this type of construction is extremely high thereby adding significantly to the cost of construction and assembly time.
The U.S. Pat. No. 3,426,623 to Abbott utilizes synchronizer detector rings which can be formed as sheet steel pressings having axial extensions which are disposed in recesses in the coupling sleeve. However, in this patent the synchronism detection rings are always biased by spring washers into engagement with the gears so that there is always frictional drag between the rings and the gears which will create excessive heat and wear and cause a loss of power. Furthermore, due to the constant spring force on the synchronizer rings the circumferential movement of the synchronizer rings relative to the coupling sleeve must always be accomplished against the resistance of this spring force thereby rendering it difficult to align the axial projections with the recesses in the coupling sleeve to facilitate positive engagement of the coupling sleeve with the gear.